Dissociation and dissociative disorders
The dissociative disorders are a group of mental disorders that affect consciousness and are defined as causing significant interference with the patient's general functioning, including social relationships and employment.
Dissociation is a mechanism that allows the mind to separate or compartmentalize certain memories or thoughts from normal consciousness. These split-off mental contents are not erased. They may resurface spontaneously or be triggered by objects or events in the person's environment.
Dissociation is a process that occurs along a spectrum of severity. If someone experiences dissociation, it does not necessarily mean that that person has a dissociative disorder or other mental illness. A mild degree of dissociation occurs with some physical stressors; people who have gone without sleep for a long period of time, have had "laughing gas" for dental surgery, or have been in a minor accident often have brief dissociative experiences. Another commonplace example of dissociation is a person becoming involved in a book or movie so completely that the surroundings or the passage of time are not noticed. Another example might be driving on the highway and taking several exits without noticing or remembering. Dissociation is related to hypnosis in that hypnotic trance also involves a temporarily altered state of consciousness. Most patients with dissociative disorders are highly hypnotizable.
People in other cultures sometimes have dissociative experiences in the course of religious (in certain trance states) or other group activities. These occurrences should not be judged in terms of what is considered "normal" in the United States.
Moderate or severe forms of dissociation are caused by such traumatic experiences as childhood abuse, combat, criminal attacks, brainwashing in hostage situations, or involvement in a natural or transportation disaster. Patients with acute stress disorder, post-traumatic stress disorder (PTSD), conversion disorder, or somatization disorder may develop dissociative symptoms. Recent studies of trauma indicate that the human brain stores traumatic memories in a different way than normal memories. Traumatic memories are not processed or integrated into a person's ongoing life in the same fashion as normal memories. Instead they are dissociated, or "split off," and may erupt into consciousness from time to time without warning. The affected person cannot control or "edit" these memories. Over a period of time, these two sets of memories, the normal and the traumatic, may coexist as parallel sets without being combined or blended. In extreme cases, different sets of dissociated memories may cause people to develop separate personalities for these memories— a disorder known as dissociative identity disorder (formerly called multiple personality disorder).
Dissociative amnesia is a disorder in which the distinctive feature is the patient's inability to remember important personal information to a degree that cannot be explained by normal forgetfulness. In many cases, it is a reaction to a traumatic accident or witnessing a violent crime. Patients with dissociative amnesia may develop depersonalization or trance states as part of the disorder, but they do not experience a change in identity.
Dissociative fugue is a disorder in which a person temporarily loses his or her sense of personal identity and travels to another location where he or she may assume a new identity. Again, this condition usually follows a major stressor or trauma. Apart from inability to recall their past or personal information, patients with dissociative fugue do not behave strangely or appear disturbed to others. Cases of dissociative fugue are more common in wartime or in communities disrupted by a natural disaster.
Depersonalization disorder is a disturbance in which the patient's primary symptom is a sense of detachment from the self. Depersonalization as a symptom (not as a disorder) is quite common in college-age populations. It is often associated with sleep deprivation or "recreational" drug use. It may be accompanied by "derealization" (where objects in an environment appear altered). Patients sometimes describe depersonalization as feeling like a robot or watching themselves from the outside. Depersonalization disorder may also involve feelings of numbness or loss of emotional "aliveness."
Dissociative identity disorder (DID)
Dissociative identity disorder (DID) is considered the most severe dissociative disorder and involves all of the major dissociative symptoms. People with this disorder have more than one personality state, and the personality state controlling the person's behavior changes from time to time. Often, a stressor will cause the change in personality state. The various personality states have separate names, temperaments, gestures, and vocabularies. This disorder is often associated with severe physical or sexual abuse, especially abuse suffered during childhood.
Dissociative disorder not otherwise specified (DDNOS)
DDNOS is a diagnostic category ascribed to patients with dissociative symptoms that do not meet the full criteria for a specific dissociative disorder.
Rebecca J. Frey, Ph.D.